The present invention relates to a polymeric label and, more specifically, to a clear polymeric label that includes a delaminatable mask layer.
Polymeric labels are applied to a wide variety of bottles and containers in order to provide, for example, information about the product being sold or to display a trade name or logo. Polymeric labels can provide various advantageous characteristics not provided by paper labels, such as durability, strength, water resistance, curl resistance, abrasion resistance, gloss, transparency, and others. However, the use of polymeric labels poses various challenges.
For example, the unique characteristics of polymeric labels can make them unsuitable for conventional manufacturing techniques. The application of paper labels to glass and plastic containers using water-based adhesives is still one of the most prevalent labeling techniques presently used. Consequently, there are many existing machines that have been installed for this type of labeling technique. These cut label techniques using water-based adhesives work well with paper based labels applied to a glass, plastic or metal substrate because the wet adhesive wicks into the paper label which breathes. This release of the adhesive moisture through the paper labels allows the adhesive to fully dry.
This technique does not work well, however, on polymeric labels because the polymeric label does not permit the moisture from the adhesive to wick through. This can make the polymeric labels prone to “swimming” or moving from the desired label location during down stream processing. The trapping of moisture in the glue can also cause the glue to remain somewhat tacky. Thus, if the polymeric label should be removed, for example, by a consumer, the consumer may come into contact with the tacky glue.
U.S. Pat. No. 6,306,242 issued to Dronzek attempts to address this problem by applying a hydrophilic layer to the polymeric layer in order to absorb a portion of the water from the water-based adhesive. However, hydrophilic coatings or a coextruded hydrophilic layer tends to absorb water from the atmosphere in humid conditions thereby hindering the ability of the hydrophilic layer to bond with the adhesive layer. In addition, the hydrophilic layer can lose water to the atmosphere in dry conditions. This gain and loss of moisture can cause the label to curl thereby hindering label application.
The desire to use water-based adhesives with clear polymeric labels poses additional problems. For example, coatings (such as the mentioned hydrophilic coatings) can increase the opacity or haze of the label. In addition, the adhesive itself, or the moisture released from the adhesive upon drying, can increase the haze of the label.
Accordingly, there is a need in the art for a clear polymeric label that can be used with water-based adhesives without a substantial increase in opacity. There is also a need in the art for a clear polymeric label that delaminates upon attempting removal of the label from a container, thereby leaving a mask layer over any adhesive that may remain tacky.